PI/PO test on that first disc you mentioned burning. You can then save the results as a .png and (hopefully) attach the file here so we can see how well the drive burned the disc. If you don't want it to take 30 minutes you can click on Preferences for the PI/PO and change "High Accuracy" to "Good Accuracy" which will take 15 minutes instead while still providing an accurate assessment of the burn's quality.

I ran the PI/PO test (SUM8 Test)at High Accuracy and I did't change any settings in the Preferences area. I don't know if I should or shouldn't have. The dvd was burned using Dvd shrink V3.2 There was compression applied to the dvd. It was a Verbatim 16x DVD+R. Also, I was using my computer while it encoded and burned. Here's what I got:

Pop the disc you burned into the Plextor drive, then run Q-Check PI/PO. Once it finishes right click on the graph it produces and save it as image, make sure to change the setting from BMP to PNG. Then save it as whatever and then upload it.

Well, the closer the readings are to the bottom the better. And the one you posted was GREAT! I can't wait to get my hands on the Plextor PX-716A!!! I can't seem to find them available anywhere. Especially with a review like this: http://tinyurl.com/6lxs7